Percutaneous transluminal coronary angioplasty (PTCA) is a procedure for treating heart disease. This procedure generally entails introducing a catheter assembly into the cardiovascular system of a patient via the brachial or femoral artery and advancing the catheter assembly through the coronary vasculature until a balloon portion thereon is positioned across an occlusive lesion. Once in position across the lesion, the balloon is inflated to a predetermined size to radially compress against the atherosclerotic plaque of the lesion to remodel the vessel wall. Subsequently, the balloon is deflated to allow the catheter assembly to be withdrawn from the vasculature.
While PTCA is widely used, it suffers generally from two unique problems. First, the blood vessel may suffer acute occlusion immediately after or within the initial hours after the dilation procedure. Such occlusion is referred to as “abrupt closure.” Abrupt closure occurs in approximately five percent of cases in which PTCA is employed. The primary mechanisms of abrupt closures are believed to be elastic recoil, vasospasm, arterial dissection, and/or thrombosis. The second problem associated with this procedure is the re-narrowing of an artery after an initially successful angioplasty. This re-narrowing is referred to as “restenosis,” which typically occurs within the first six months after angioplasty. Restenosis is believed to be due to, among other things, the proliferation and migration of cellular components from the arterial wall, as well as through geometric changes in the arterial wall referred to as “remodeling.”
To reduce occlusion of the artery, and the development of thrombosis and/or restenosis, an expandable interventional device or prosthesis, one example of which includes a stent, may be implanted in the lumen to maintain the vascular patency. Additionally, to better effectuate the treatment of such vascular disease, it may be preferable to load an intraluminal device or prosthesis with one or more beneficial agents, such as antiproliferatives, for delivery to a lumen. One commonly applied technique for the local delivery of a drug is through the use of a polymeric carrier coated onto the surface of a stent, as disclosed in Berg et al., U.S. Pat. No. 5,464,650, the disclosure of which is incorporated herein by reference thereto. Such conventional methods and products generally have been considered satisfactory for their intended purpose.
However, implantable devices, such as stents may be difficult to coat without webbing, cobwebs, or other defects due to their generally intricate geometry. They may also be difficult to uniformly coat (i.e. on the ablumenal, luminal, and sidewall surfaces). Because of these challenges, many commercialized drug eluting stents are being coated by a spray process. However, spray coating may suffer generally from the following: reduced coating speed, reproducibility, and/or coating efficiency (i.e. the amount of material sprayed actually coating the device).
Accordingly, it may be desirable to provide methods for applying an application material to an implantable device.